// console.log('Object is what?')
var o={'a':1};
const num=null;
let b;
console.log(o.hasOwnproperty('a','-----'));
console.log(!num,! b,'------');
console.log(typeof o);
console.log(typeof num);//前三位表示数据类型 000  typeof 在读取数据类型的时候只读取前三位二进制数
console.log(Object.prototype.toString.call(num));
console.log(o.toString());
console.log(num.toString());
console.log(Object.prototype.isPrototypeOf(o));